This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. For dystonia patients who do not respond to medical therapy, surgical treatment with deep brain stimulation (GPi DBS) can reduce symptoms. However, the precise mechanism by which this intervention works is unknown. We hypothesize that dystonia is caused by a disturbance of the functional connections between the frontal cerebral cortex and subcortical brain regions involved in movement regulation. In the proposed studies, we will test the hypothesis whether this functional disturbance can be corrected by effective GPi DBS.